Ben Chuanlong Du's Blog

It is never too late to learn.

Latency Numbers Programmers Should Know

Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!

Latency Operations
<=1ns
  • accessing CPU registers
  • CPU clock cycle
  • L1 cache
1-10ns
  • L2 cache
  • branch mispredict
10-100ns
  • L3 cache
  • mutex lock/unlock
  • main memory referencing
100-1000ns
  • trapping of system call
  • md5 hash of an u64
1-10us
  • process context switching
  • compress 1k with zippy
  • memory copy of 64k
10-100us
  • network proxy / http request
  • read 1M from memory
  • SSD latency (read a 8k page)
100-1000us
  • SSD write latency / write a page
  • intra-zone networking round trip
  • memcache/redis get operation
    (measured by client including network round trip)
1-10ms
  • inter-zone networking latency
  • hard drive latency
10-100ms
  • network round trip between US coasts
  • network round trip between US east coast and Europe
  • read 1G from memory
100-1000ms
  • bcypt a password
  • TLS handshae (250-500ms)
  • network round trip from US west coast to Singapore
  • read 1G from SSD
>=1s
  • transfer 1G over a network in the same region

References

Comments